CD47-SIRP? Interactions Regulate Macrophage Uptake of Plasmodium falciparum-Infected Erythrocytes and Clearance of Malaria In Vivo.
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ABSTRACT: CD47 engagement by the macrophage signal regulatory protein alpha (SIRP?) inhibits phagocytic activity and protects red blood cells (RBCs) from erythrophagocytosis. The role of CD47-SIRP? in the innate immune response to Plasmodium falciparum infection is unknown. We hypothesized that disruption of SIRP? signaling may enhance macrophage uptake of malaria parasite-infected RBCs. To test this hypothesis, we examined in vivo clearance in CD47-deficient mice infected with Plasmodium berghei ANKA and in vitro phagocytosis of P. falciparum-infected RBCs by macrophages from SHP-1-deficient (Shp-1(-/-)) mice and NOD.NOR-Idd13.Prkdc(scid) (NS-Idd13) mice, as well as human macrophages, following disruption of CD47-SIRP? interactions with anti-SIRP? antibodies or recombinant SIRP?-Fc fusion protein. Compared to their wild-type counterparts, Cd47(-/-) mice displayed significantly lower parasitemia, decreased endothelial activation, and enhanced survival. Using macrophages from SHP-1-deficient mice or from NS-Idd13 mice, which express a SIRP? variant that does not bind human CD47, we showed that altered SIRP? signaling resulted in enhanced phagocytosis of P. falciparum-infected RBCs. Moreover, disrupting CD47-SIRP? engagement using anti-SIRP? antibodies or SIRP?-Fc fusion protein also increased phagocytosis of P. falciparum-infected RBCs. These results indicate an important role for CD47-SIRP? interactions in innate control of malaria and suggest novel targets for intervention.
SUBMITTER: Ayi K
PROVIDER: S-EPMC4936360 | biostudies-literature | 2016 Jul
REPOSITORIES: biostudies-literature
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